I understand what you are saying, but these things can be quantified and accounted for in economic models. We can wave hands all day about "I think the economy would do this" but that is often the enemy of applied economics (heavily mathematical) and progress. There is a point when the incentives for the company can turn negative for the community. There is also the consideration in the community that those taxpayers (and voters) do not want to subsidize a massive corporation's shareholders.
Politicians can be aware of this point, but with a massive corporation trying to pit them all against each other for its own gain, competition will erode those profits to or even past the point of neutral cost-benefit to the community. As Peter Thiel likes to point out "Competition is for losers."